Ozone (O3), a naturally occurring gas in the upper atmosphere, has long been recognized as an effective and powerful disinfectant. As a highly reactive gas composed of three oxygen atoms, ozone gas rapidly oxidizes bacteria and viruses it comes in contact using the third, loosely-bonded oxygen atom, then reverts safely back into oxygen (O2), making it one of the most environmentally friendly cleaning methods available. In its gaseous form, ozone flows over surfaces, travels deep into holes, surfaces, fabrics and crevices, and disperses thoroughly into the ambient environment. Ozone cleaning and sterilization offers a number of advantages: it produces no toxic waste, does not require the handling of dangerous gas cylinders, and generally poses no threat to the environment or the user's health. Ozone can also be used to eliminate or reduce unpleasant odors on or within the same types of materials by oxidizing the compounds that produce those odors.
As a result, ozone gas may be used in mold remediation, air sanitizing, water purification, commercial laundering, and equipment sterilization such as medical devices sterilization. It is known that all devices, instruments and accessories used for medical purposes (collectively “medical devices”) require varying degrees of cleaning, disinfection and sterilization before these devices can be reused on the same or different patient. Medical devices with surface irregularity or complexity, such as hoses and tubes, are difficult to completely clean, disinfect and sterilize. These hard-to-reach places are particularly prone to bacteria, mold and microorganism growth and accumulation, as medical devices often come into contact with various body fluids, water and chemical agents. To avoid serious health risks, hospitals, surgical centers, medical test centers, sleep centers, nursing homes and the like often opt for single-use or disposable medical devices, resulting in a significant expense with adverse environmental impact. For reusable medical devices, reprocessing is labor-intensive, time-consuming, expensive, and often requires a specific reprocessing regimen. Preferably, after each use, reusable medical devices and any residual contaminants are kept moist in order to make the cleaning process easier and more effective. Thorough manual and mechanical cleaning is needed for all reusable medical devices prior to disinfection or sterilization. This step requires the use of proper cleaning solutions (e.g., water, detergent, surfactants, buffers, chelating agents, or enzymes) and processes to assure that all surfaces, internal and external, are completely free of bio-burden. Finally, the devices should be thoroughly rinsed to remove all residual bio-burden and detergent, and then dried properly.
A medical device may be classified in terms of potential risk of infection towards a patient or between patients if the medical device is reused. Examples of critical medical devices may include surgical instruments, irrigation systems for sterile instruments in sterile tissues, endoscopes and endoscopic biopsy accessories. These critical devices are introduced directly in the bloodstream or may contact normally sterile tissue and have a possibility of microbial transmission if the medical devices are not sterile, thus strict cleaning and sterilization thereof is required. Semi-critical medical devices may be categorized as devices that contact mucous membranes, for example, duodenoscopes, endotracheal tubes, bronchosopes, laryngosopes, blades and other respiratory equipment, esophageal manometry probes, diaphragm fitting rings and gastrointestinal endoscopes. Disinfection and/or sterilization are required before such a semi-critical medical device can be reused. Non-critical medical devices may have surface contacts with a patient's skin but do not penetrate the skin. Non-critical devices also include devices that may become contaminated with microorganisms and organic soil during patient care, such as infusion pumps, and ventilators. For example, continuous positive airway pressure (CPAP) devices are prone to bacterial build-up because of humidified air and contact with a patient's mouth. Many of the devices described above include passageways that are difficult to clean, disinfect and sterilize, such as endoscopes, probes, ventilators and specifically CPAP device parts, CPAP hoses, and CPAP facemasks.
It is thus desirable to provide ozone sanitizing system and method for cleaning, disinfecting and sterilizing various objects such as medical device components and parts that come in different shapes and sizes.
It is known that ozone concentration is important to the killing of pathogens on an item being sanitized. However, when an ozone gas generator is used to generate ozone gas with a relatively high concentration, it may require more power to be provided to the ozone gas generator. For a rechargeable or portable sanitizing system using ozone gas, a relatively high ozone concentration output may require a battery with high capacity for a portable ozone gas generator or a limited number of ozone cleaning cycles. Generally speaking, the bigger the battery, the higher the capacity of the battery and a heavier and bulkier design for the ozone gas generator.
In addition, where the ozone/air mixture used for sanitizing is continuously injected into a vessel with an exhaust port during the sanitizing cycle, the ozone in the ozone/air mixture discharged from the exhaust port may need to be neutralized. This can reduce the life cycle of the neutralizing material versus a system where only the ozone remaining after the sanitizing cycle is neutralized. Moreover, it may be desirable to rapidly increase the concentration of ozone in the vessel to reduce the time required for sanitation. If the air/ozone mixture is discharged through an exhaust port, the amount of ozone being discharged is subtracted from the ozone in the sanitizing vessel. By recirculating the air/ozone mixture in the vessel such that no ozone is discharged from the vessel during the sanitizing cycle, the concentration of ozone increases more rapidly.
It is thus desirable to provide an ozone recirculation system and method for cleaning, disinfecting and sterilizing various objects with increased ozone concentration without requiring an ozone gas generator having a higher output or requiring the underlying system to continuously neutralize ozone gas that is discharged during the sanitizing cycle. To improve the efficacy of an ozone sanitizing system, it is also desirable to inflate a vessel made of a flexible material and fully expose surfaces of objects stored therein for ozone treatment. Further, it is desirable for an ozone sanitizing system to automatically identify the size of the vessel and determine an appropriate ozone treatment duration.